fix: validate gossip message for clock skew (#2119)

## Motivation

- Messages were found in gossip with very high timestamps that would be
very far in the future

## Change Summary

- Reject gossip messages that are more than 10 minutes in the future 

## Merge Checklist

_Choose all relevant options below by adding an `x` now or at any time
before submitting for review_

- [x] PR title adheres to the [conventional
commits](https://www.conventionalcommits.org/en/v1.0.0/) standard
- [x] PR has a
[changeset](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#35-adding-changesets)
- [x] PR has been tagged with a change label(s) (i.e. documentation,
feature, bugfix, or chore)
- [ ] PR includes
[documentation](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#32-writing-docs)
if necessary.
- [x] All [commits have been
signed](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#22-signing-commits)

## Additional Context

If this is a relatively large or complex change, provide more details
here that will help reviewers


<!-- start pr-codex -->

---

## PR-Codex overview
This PR focuses on fixing clock skew validation for gossip messages in
the `@farcaster/hubble` module.

### Detailed summary
- Added validation for clock skew in gossip messages
- Introduced `ALLOWED_CLOCK_SKEW_SECONDS` constant
- Improved error handling for future timestamps in gossip messages

> ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your
question}`

<!-- end pr-codex -->

.changeset/silent-planes-promise.md

@@ -0,0 +1,5 @@
+---
+"@farcaster/hubble": patch
+---
+
+fix: validate gossip message for clock skew

apps/hubble/src/hubble.ts

@@ -18,7 +18,6 @@ import {
   Message,
   OnChainEvent,
   onChainEventTypeToJSON,
-  toFarcasterTime,
   UserNameProof,
   validations,
 } from "@farcaster/hub-nodejs";
@@ -127,6 +126,7 @@ export const FARCASTER_VERSIONS_SCHEDULE: VersionSchedule[] = [
 
 const MAX_CONTACT_INFO_AGE_MS = 1000 * 60 * 60; // 60 minutes
 const CONTACT_INFO_UPDATE_THRESHOLD_MS = 1000 * 60 * 30; // 30 minutes
+const ALLOWED_CLOCK_SKEW_SECONDS = 60 * 10; // 10 minutes
 
 export interface HubInterface {
   engine: Engine;
@@ -1274,6 +1274,24 @@ export class Hub implements HubInterface {
     const messageFirstGossipedTime = gossipMessage.timestamp ?? 0;
     const gossipMessageDelay = currentTime - messageFirstGossipedTime;
     if (gossipMessage.timestamp) {
+      if (gossipMessage.timestamp > currentTime && gossipMessage.timestamp - currentTime > ALLOWED_CLOCK_SKEW_SECONDS) {
+        log.error(
+          {
+            allowedClockSkew: ALLOWED_CLOCK_SKEW_SECONDS,
+            currentTime,
+            gossipMessageTimestamp: gossipMessage.timestamp,
+            source: source.toString(),
+          },
+          "Received gossip message with future timestamp",
+        );
+        await this.gossipNode.reportValid(msgId, peerIdFromString(source.toString()).toBytes(), false);
+        return err(
+          new HubError(
+            "bad_request.invalid_param",
+            "Invalid Farcaster timestamp in gossip message - future timestamp found in seconds from Farcaster Epoch",
+          ),
+        );
+      }
       // If message is older than seenTTL, we will try to merge it, but report it as invalid so it doesn't
       // propogate across the network
       const cutOffTime = getFarcasterTime().unwrapOr(0) - GOSSIP_SEEN_TTL / 1000;